We recently acquired a Dell MD3200 and MD1200 6Gb/sec shared SAS storage system and I have spent a couple of days setting up some tests to see how it compares to our old iSCSI EMC Clariion. Wasn't really a fair fight, given that the EMC had 500GB 7200rpm SATA disks in it, whereas the new systems had 450GB 15000rpm SAS in the MD3200 and 2TB 7200rpm nearline SAS in the MD1200.
Big caveat on the following test results ... all are the result of testing a single VM ... I do not (yet) have any results with a multipleVM shared workloads on shared LUNs, so I haven't tested the impact of contention, locking, etc.
Tests were done by running simple IOMETER jobs. Results per job were cross-checked with 'esxtop' to ensure that they roughly matched (they did). I installed a Windows Server 2008 R2 VM and created 100GB vmdk's on each storage tier. I tested with 5-disk and 6-disk RAID5 as well as a few tests with a 6-disk RAID10.
I had a guess at constructing some sample workloads to simulate SQL data (reading/writing 64KB chunks of data) as well as simulating retrieval of data for backups. My guess as to how these might work could be way off! If anyone thinks so and can suggest improvements to the IOMETER test workloads, I am happy to receive that feedback and can probably repeat the tests with different parameters.
Some of the conclusions I reached (some of which came as a surprise to me, and some which didn't!):
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